| 1. |
- Jiang, Ziwei, et al.
(författare)
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Characterterization of multi-scale nanosilver paste reinforced with SIC particles
- 2020
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Ingår i: China Semiconductor Technology International Conference 2020, CSTIC 2020.
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Konferensbidrag (refereegranskat)abstract
- Nanosilver paste with high operation temperature and low sintering temperature has attracted more and more attention for its promising application in high power devices. In this paper, the thermal properties of multi-scale nanosilver paste composed of nanometer and micrometer silver particles, and Ag-coated SiC particles were investigated. The thermal conductivity of multi-scale nanosilver paste increases with the increasing amount of SiC particles with Ag coating. The maximum value of Vickers hardness for multi-scale nanosilver paste with 0.5 wt.% Ag-coated SiC particles were 24.
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| 2. |
- Liu, Hao, et al.
(författare)
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Thermally Conductive Graphene Film/Indium/Aluminum Laminated Composite by Vacuum Assisted Hot-pressing
- 2020
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Ingår i: 2020 21ST INTERNATIONAL CONFERENCE ON ELECTRONIC PACKAGING TECHNOLOGY (ICEPT). - 9781728168265
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Konferensbidrag (refereegranskat)abstract
- In order to meet the ever more demanding requirements of modern thermal management with the increasing high power density, an easy-fabricated laminated graphene film/indium/aluminum (GF/In/Al) composite was developed. The GF was fabricated through assemble graphene oxide (GO) sheets in a layer-by-layer structure and then subjected to graphitization process at high temperature as well as press forming process. The fabricated GF exhibits ultrahigh in-plane thermal conductivity together with good tensile strength. The GF/In/Al laminated composite was fabricated by hot-pressing indium coated GF and Al layers in vacuum environment. The indium layer was easily coated onto the GF due to its low melting point along with good flowing property. The thermal resistance measurements show that the indium bonding possess greater preponderance of reducing contact resistance than without bonding material and thermal conductive adhesive (TCA) bonding, because indium layer could fill the gap between GF and Al layers, and provide more stable connection. The results show that the obtained laminated composite could be potentially used in the thermal management of high power systems.
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| 3. |
- Zhang, Maomao, et al.
(författare)
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Effect of pressure during graphitization on mechanical properties of graphene films
- 2019
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Ingår i: 2019 20th International Conference on Electronic Packaging Technology, ICEPT 2019.
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Konferensbidrag (refereegranskat)abstract
- Graphene films (GFs) can be used in the field of electronics cooling, owing to many outstanding properties. In the present paper, GFs samples were graphitized at different pressures to study their effect on the mechanical properties. The elastic modulus and hardness of GFs were measured by nanoindentation and the tensile strength of GFs were obtained by stretching GFs in a tensile tester. Meanwhile, GFs were characterized by X-ray diffraction(XRD), Scanning electron microscopy (SEM) and Raman spectroscopy. The results show that the modulus, hardness and tensile strength of GFs were strongly influenced by the defect and wrinkles among other things.
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| 4. |
- Chen, Shujing, et al.
(författare)
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Scalable production of thick graphene films for next generation thermal management applications
- 2020
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Ingår i: Carbon. - : Elsevier BV. - 0008-6223. ; 167, s. 270-277
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Tidskriftsartikel (refereegranskat)abstract
- With the increasing demand on integration and better performance of portable electronics devices, the system operation temperatures are expected to continue to increase, leading eventually to degeneration in functional performance and reliability. Therefore, demand for thermal management materials that effectively spread heat and reduce heat density is urgent. The existing solution of pyrolytic graphite film (PGF) is unsatisfactory due to their low heat flux carrying capacity or low thermal conductivity, as well as poor mechanical performance. This work solves the problem by substituting ultra-thick (>75 mm) graphene film (GF) for PGF, offering more than three times higher heat flux carrying capacity. The conjugation of large crystallinity and firm structures endows GFs with excellent thermal conductive performance (up to 1204 +/- 35 W m(-1) K-1), great heat flux carrying capacity, and good foldability (5000 cycles folding). In addition to this, such a GF is produced based on an economically efficient and quasi industrial method incorporating continuous high-pressure homogenization processing (HPH), indicating an enormous potential as a new pathway to thermal management applications.
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| 5. |
- Guo, Sihua, et al.
(författare)
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Synergistic Toughening of Graphene Films by Addition of Hydroxylated Carbon Nanotube
- 2021
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Ingår i: 2021 23rd European Microelectronics and Packaging Conference and Exhibition, EMPC 2021.
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Konferensbidrag (refereegranskat)abstract
- Graphene attracts great attention due to its excellent properties. However, the mechanical of assembled graphene-based film is usually inferior than its inherent mechanical properties. Herein, we construct a high-performance graphene-based film via vacuum filtration process by using graphene as matrix and hydroxylated Carbon Nanotube (CNT) as reinforcement agent. The synergistic interaction of hydrogen bonds between CNT and graphene Oxide (GO) and ionic bonds between Fe2+ on CNT and GO significantly improve the mechanical properties of free-standing and flexible rGO/CNT film. Scanning Electron Microscopic (SEM) imaging and stress transfer mechanism analysis show that the introduction of CNT can hinder the slippage of GO sheets and promote the stress transfer under the continuous loading. The obtained rGO/CNT film shows high toughness of 3 MJ/m3, which is 3.6 times higher than that of GO sheets. This facile and scalable strategy can pave the way for the fabrication of high-performance graphene-based film in various applications.
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| 6. |
- Wang, Chao, et al.
(författare)
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Rebuilding the vibrational wavepacket in TRAS using attosecond X-ray pulses
- 2024
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Ingår i: Communications Physics. - : Springer Nature. - 2399-3650. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- Time-resolved X-ray photoelectron spectroscopy (TXPS) is a well-established technique to probe coherent nuclear wavepacket dynamics using both table-top and free-electron-based ultrafast X-ray lasers. Energy resolution, however, becomes compromised for a very short pulse duration in the sub-femtosecond range. By resonantly tuning the X-ray pulse to core-excited states undergoing Auger decay, this drawback of TXPS can be mitigated. While resonant Auger-electron spectroscopy (RAS) can recover the vibrational structures not hidden by broadband excitation, the full reconstruction of the wavepacket is a standing challenge. Here, we theoretically demonstrate how the complete information of a nuclear wavepacket, i.e., the populations and relative phases of the vibrational states constituting the wavepacket, can be retrieved from time-resolved RAS (TRAS) measurements. Thus, TRAS offers key insights into coupled nuclear and electronic dynamics in complex systems on ultrashort timescales, providing an alternative to leverage femtosecond and attosecond X-ray probe pulses.
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| 7. |
- Wang, Chao, et al.
(författare)
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Time-Resolved Resonant Auger Scattering Clocks Distortion of a Molecule
- 2023
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Ingår i: The Journal of Physical Chemistry Letters. - : American Chemical Society (ACS). - 1948-7185. ; 14:24, s. 5475-5480
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Tidskriftsartikel (refereegranskat)abstract
- Resonant Auger scattering (RAS) provides information on the core-valence electronic transition and impresses a rich fingerprint of the electronic structure and nuclear configuration at the time-initiating RAS process. Here, we suggest using a femtosecond X-ray pulse to trigger RAS in a distorted molecule, which is generated from the nuclear evolution on a valence excited state pumped by a femtosecond ultraviolet pulse. With the time delay varied, the amount of molecular distortion can be controlled and the RAS measurements imprint both their electronic structures and changing geometries. This strategy is showcased in H2O prepared in an O-H dissociative valence state, where molecular and fragment lines appear in RAS spectra as signatures of ultrafast dissociation. Given the generality of this approach for a broad class of molecules, this work opens a new alternative pump-probe technique for mapping the core and valence dynamics with ultrashort X-ray probe pulses.
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